Gasoline containing azines



United States Patent GASOLINE CONTAINING AZ'INES Bruno H. Wojcik, Niagara Falls, N.Y., assignor to Olin Mathieson Chemical Corporation, a corporation of Virginia No Drawing. Filed Feb. 21, 1956, Ser. No. 566,783

7 Claims. (Cl. 4463) This invention relates to improvements in motor fuels, particularly in gasoline fuels for internal combustion engines. More particularly, it relates to improvements effected in gasoline motor fuels by the incorporation therein of minor proportions of azines.

Gasoline suitable for use as a motor fuel is a complex mixture consisting largely of a variety of hydrocarbons and usually includes one or more non-hydrocarbon materials added thereto to improve the storage and operating'characteristics of the fuel.

Few modern gasolines are straight run fuels and the mixture usually contains a substantial fraction of hydrocarbons obtained by cracking, isomerization, alkylation, polymerization, reforming, hydroforming or other operations. Many of these processes are designed to produce hydrocarbons which when blended with straight-run gasoline will improve the anti-knock value. While these hydrocarbons have high anti-knock blending value, they are characteristically less stable than the saturated hydrocarbons of straight-run gasoline. The processed hydrocarbons are notably subject to oxidation and polymerization in storage with the formation of gummy products deleterious to storage containers and pumps, as well as feed lines, pumps and carburetor in the automotive vehicle. In addition, they may give rise in the engine to materials which at normal temperatures of operation form resinous deposits on pistons, rings, cylinder walls and bearings which interfere with proper operation of the automotive engine. Numerous inhibitors are commercially available for stabilization of gasoline in these respects and to improve storage and operating characteristics of the fuel by avoiding the formation of resinous products of these unstable hydrocarbons. Most of the inhibitors are compounds of relatively high molecular weight compared with gasoline hydrocarbons and are likely to remain as residues on evaporation of the fuel.

Motor gasoline is also usually blended with appropriate proportions of a butane fraction, particularly for winter use to provide sufiicient volatility for easy starting. Many automotive engines, however, are not maintained in good operating condition and difiicult starting is characteristic of such engines even though the refiner provides a suitable fuel for engines in average or better condition. Added tricresyl phosphate is advertised as improving starting characteristics.

Tetraethyl lead is commonly added to improve the anti-knock value of the gasoline and usually a mixture of halogen compounds is simultaneously added to insure the vaporization of the combustion products of the tetraethyl lead. In addition, other materials may be added to gasoline for various purposes including light lubricating oils for upper cylinder lubrication and many other dopes for various purposes.

The use of unsubstituted hydrazine as an additive is highly impractical as hydrazine is substantially insoluble in hydrocarbons. It cannot, therefore, be incorporated in the fuel, but must be injected at some suitable posi- 2,969,278 Patented Jan. 24, 1961 tion in the fuel line or air intake by a suitable clevice.v

Furthermore, the presence of minor amounts of unsubstituted hydrazine drastically reduces the octane rating of gasoline by 10 or more octane units.

According to the present invention, the addition of minor proportions of azines or mixtures thereof to gasoline surprisingly improves the storage, starting and other operating characteristics of the fuel. These azines have the formula:

wherein R and R are selected from the group comprising aliphatic hydrocarbon, alicyclic hydrocarbon, aromatic hydrocarbon and heterocyclic substituents. R, and R are selected from the group consisting of hydrogen, R and R They may be the same or different. In general, many of these azines are known to the art, Their preparations are described in Beilsteins Handbuch, vol. 1, 2nd supplement, pages 675 to 755. Those in which R and R are diiferent and R and R are different may be somewhat more difficult to prepare, however, anyone skilled in the art may find several methods to obtain them in satisfactory yields. The number of car- 'bon atoms in the above formula is preferably less than 15, however certain larger groups are also effective, up to and including about 36 carbon atoms. The substituent R groups may also carry certain innocuous groups such as, for example, a hydroxyl group or an ether group. Preferably, R R R and R are alkyl, cycloalkyl, aryl or heterocyclics containing one hetero atom.

Examples of some azines encompassed by this invention are:

. Acetaldehyde azine Butyraldehyde azine Isobutyraldehyde azine Pentaldehyde azine Benzaldehyde azine Dimethylketazine Methylethylketazine Ethylisopropylketazine Dipropylketazine Furfuralazine The azines or mixtures thereof can be dissolved to the extent of 0.1 to 2 percent by weight in gasoline to provide suitable compositions according to the present invention. Somewhat smaller or larger amounts of the azines or mixtures thereof can also be used, but preferably the amount used is within the range of from 0.5 to 1 percent by weight, based on the gasoline.

The presence of azines in gasoline improves its stability towards the action of oxygen in storage. The azines are reactive with dissolved oxygen and prevent its action on the relatively unstable hydrocarbons by reacting more readily with the oxygen dissolved from the air. This activity of the azines may not remove the necessity for incorporation of minor amounts of the usual anti-oxidants but it tends to reduce the quantity required in order to provide satisfactory stability in storage. This in turn reduces the proportion of non-volatile components in the BWOOQQUI-BU NH gasoline and effects improvement in the cleanliness of I lines, pump and carburetor.

Beneficial results are noticeable when as little as 0.1 percent by weight or less of an azine is added and quantities of 2 percent by weight or more can be used if desired. Ordinarily, within this range, material improvements are effected economically by the addition of from about 0.5 to 1 percent by weight of a suitable azine to the gasoline.

3.4 milligrams of residue.

The azines can be blended with'the gasoline in any convenient manner or at any stage. They can be added as pure compounds ,or may be diluted with one of the blending stocks to be used.

Example I A solution of 1.5 percent by weight of acetaldehyde azine in gasoline is an example of this invention.

Example ll .Anotherexample of this invention is asolution of 0.9 percent by weight of isobutyraldehyde azine in gasoline.

Example III A blend of 1 percentby weight of benzaldehyde azine and 99 percent by weight of gasoline is a further example of this invention.

Example IV An additional example of this invention is a solution 'of 2 percent by weight of furfuralazine and 98 percent by weight of gasoline.

Example V A sample of stock gasoline was tested for existent gurn according to A.S.T.M. method D381-50. Upon evaporation of 100 milliliters of sample, there remained When a 100 milliliter sample of this stock containing 1 percent by Weight of dimethylketazine was tested in a similar manner, only 2.5 milligrams of residue remained. The amount of residue was -decreasedby 26 percent.

I claim:

,1. Gasoline containing as an additive from about 0.1 to 2 percent by weight of at least one of the materials falling within the scope of the formula "wherein R and R 'areselected from the group consisting of alkyl, cycloalkyl and aryl hydrocarbon radicals and heterocyclic radicals containing one hetero oxygen atom, and R and R are selected from the group consisting of hydrogen and R and R substituents, with the proviso that the total number of carbon atoms in the material does not exceed 36.

2. The composition of claim 1 in which the gasoline contains about 0.5 to 1 percent by weight of material.

3. Gasoline containing about 0.1 to 2 percent by weight of acetaldehyde azine.

4. Gasoline containing about 0.1 to 2 percent by weight of isobutyraldehyde azine.

5. Gasoline containing about 0.1 to 2 percent by weight of benzaldehyde azine.

6. Gasoline containing about 0.1 to 2 percent by weight of furfuralazine.

7. Gasoline containing about 0.1 to 2 percent by weight of dimethylketazine.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES The Chemistry of ,Hydrazine, by Audrieth and Ogg, Wiley and Sons Inc., 1951, pages 225,, 226 and 227.

:Scientific American, vol.189, No. 1, July 1953, Hydrazine, by vLessing, pages 30 to 33.

Ind. andEng. Chem.,-.vol. 42, September 1950, Hy-

.drazinein Organic Chemistry, by Byrkit and Michalek,

pages 1862 to 1875. 

1. GASOLINE CONTAINING AS AN ADDITIVE FROM ABOUT 0.1 TO 2 PERCENT BY WEIGHT OF AT LEAST ONE OF MATERIALS FALLING WITHIN THE SCOPE OF THE FORMULA 